Interatomic potentials of metal dimers: probing agreement between experiment and advancedab initiocalculations for van der Waals dimer Cd2

The recent spectroscopy of van der Waals molecules is reviewed. Examples are presented from radio-frequency, microwave, Raman, infrared, and electronic spectroscopy. Diatomic van der Waals molecules (e.g. Ne2, Ar2, Kr2, Mg2) reveal a manifold of closely spaced vibration–rotation levels consistent with the small dissociation energies which are orders of magnitude less than for ordinary chemically bonded molecules. The (isotropic) interatomic potentials which define these molecules may be evaluated from their energy levels. Polyatomic van der Waals molecules (e.g. H2–Ar, FCl–Ar, (H2)2, (O2)2, (CO2)2) are classified according to the strength of the (anisotropic) intermolecular potential which tends to define their geometry. This classification depends on the nature of the coupling of the rotational angular momenta and leads to a labeling of the complexes as free rotor, weakly coupled, strongly coupled, or semirigid. The spectroscopic constants which are determined from the energy levels of diatomic and polyatomic van der Waals molecules can be used to better understand the intermolecular bonding which holds these molecules together.

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Exceptional in-plane and interfacial thermal transport in graphene/2D-SiC van der Waals heterostructures

Scientific Reports ◽

10.1038/s41598-020-78472-2 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Md. Sherajul Islam ◽

Imon Mia ◽

Shihab Ahammed ◽

Catherine Stampfl ◽

Jeongwon Park

Keyword(s):

Thermal Conductivity ◽

Heat Conduction ◽

Van Der Waals ◽

New Physics ◽

Infinite Length ◽

Interatomic Potentials ◽

Van Der Waals Heterostructures ◽

Functional Efficiency ◽

Out Of Plane ◽

The Impact

AbstractGraphene based van der Waals heterostructures (vdWHs) have gained substantial interest recently due to their unique electrical and optical characteristics as well as unprecedented opportunities to explore new physics and revolutionary design of nanodevices. However, the heat conduction performance of these vdWHs holds a crucial role in deciding their functional efficiency. In-plane and out-of-plane thermal conduction phenomena in graphene/2D-SiC vdWHs were studied using reverse non-equilibrium molecular dynamics simulations and the transient pump-probe technique, respectively. At room temperature, we determined an in-plane thermal conductivity of ~ 1452 W/m-K for an infinite length graphene/2D-SiC vdWH, which is superior to any graphene based vdWHs reported yet. The out-of-plane thermal resistance of graphene → 2D-SiC and 2D-SiC → graphene was estimated to be 2.71 × 10−7 km2/W and 2.65 × 10−7 km2/W, respectively, implying the absence of the thermal rectification effect in the heterobilayer. The phonon-mediated both in-plane and out-of-plane heat transfer is clarified for this prospective heterobilayer. This study furthermore explored the impact of various interatomic potentials on the thermal conductivity of the heterobilayer. These findings are useful in explaining the heat conduction at the interfaces in graphene/2D-SiC vdWH and may provide a guideline for efficient design and regulation of their thermal characteristics.

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